Flexible antenna formed of opposed convex laminated strips covered with a heat-shrunk hose

ABSTRACT

This invention relates to a laminated antenna for portable radio sets which can be bent or buckled. The antenna lamination consists of two longitudinally staggered groups of transversely cambered steel strips. These strip groups are so disposed in a mirror-inverted arrangement that a biconvex cross section is obtained. Firmly interconnected only at the base of the antenna through a holder, the entire arrangement is covered with a heatshrunk hose. The biconvex arrangement of the steel strips results in a rigidity equal in both directions of bending. The covering provides protection against atmospheric influences, contamination and injuries and prevents reflections of light.

United States Patent [191 Reiber et al.

Filed: Oct. 25, 1972 Appl. No.: 300,621

[73] Assignee:

[30] Foreign Application Priority Data Nov. 3, 197] Germany P 21 54 65] vs. C]. 343/872, 343/900 1m. 01. H01q 9/30 Field of Search 343/872, 873, 900, 71s

[5 6] References Cited UNITED STATES PATENTS 2,293,429 8/1942 Feussnev et al. 52/730 FOREIGN PATENTS OR APPLICATIONS 660,9l3 1 1/195! Great Britain 343/900 Jan. 29, 1974 526,629 6/1956 Canada 343/900 847,302 8/1952 Germany 343/900 Primary Examiner-Eli Lieberman Attorney, Agent, or Firm-C. Cornell Remsen, Jr. et

[57] ABSTRACT This invention relates to a laminated antenna for portable radio sets which can be bent or buckled. The antenna lamination consists of two longitudinally staggered groups of transversely cambered steel strips. These strip groups are so disposed in a mirror-inverted arrangement that a biconvex cross section is obtained. Firmly interconnected only at the base of the antenna through a holder, the entire arrangement is covered with a heat-shrunk hose. The biconvex arrangement of the steel strips results in a rigidity equal in both directions of bending. The covering provides protection against atmospheric influences, contamination and injuries and prevents reflections of light.

9 Claims, 4 Drawing Figures vEia PATENTEDJmsmM SHEU 2 UP 2 liillil \llllllillilllllllll III!lillllilillllillllllll FLEXIBLE ANTENNA FORMED OF OPPOSED CONVEX LAMINATED STRIPS COVERED WITH A IIEAT-SIIRUNK HOSE BACKGROUND OF THE INVENTION The present invention relates to a bendable and buckling laminated antenna for portable radio sets or the like, consisting of several layers of hollow steel strips of different length which are positively interconnected at the base through a holder.

As a rule, portable radio sets, particularly radiotelephones, use telescopic antennas, which are telescoped when required, thus permitting easy handling and stowage of the non-operational sets.

However, practical telescopic antennas are for normal usage, they are little suited for use under adverse conditions such as on building sites, during expeditions, in emergencies and in the military field. Even slight buckling of the antenna generally results in telescoping being impossible or presenting difficulties. In addition, such antennas are not protected against atmospheric influences and contamination, which fact may also lead to an electrical failure of the antenna. Furthermore, in certain applications, the reflecting characteristic of the mirror-finished surface is considered disturbing.

For this reason, so-calledlaminated antennas have been used, which consist of a lamination of several socalled hollow steel strips (steel strips cambered transversely to the longitudinal direction) of different length. Staggered in length from the inside toward the outside, the steel strips are firmly interconnected at the base via a holder, the latter simultaneously representing a plug-and-socket and/or screw connection, so that the antenna can be electrically and mechanically connected with the associated set. In the longitudinal direction, the interleaved steel strips are provided at certain intervals with matching oblong holes. Sliding therein are rivets, which hold the hollow steel strips together. On its outside, the antenna is provided with a coat of paint as a protection against corrosion and reflection.

The principal advantage of this type of antenna is that it is self-erecting, highly flexible, and capable of being bent and buckled without being damaged. If it is out of operation, it can be folded together and stowed away in a special antenna compartment of the carrying case for the radio set.

However, the known design just described has the disadvantage of showing a varying mechanical behavior in the two directions of buckling due to the unidirectional position of the individual hollow steel strips. In addition, contamination may be caused by the penetration of foreign matter and moisture between the laminated strips, which may result in mechanical damage and corrosion and, consequently, in a deterioration of the antennas electrical characteristics. Furthermore, the coat of paint may suffer, and visible bright spots may emerge. Also, injuries cannot be excluded due to the sharp metallic edges.

SUMMARY OF THE INVENTION It is the object of the present invention to provide a laminated antenna which avoids the above-mentioned disadvantages.

The invention is characterized in that the antenna lamination consists of two longitudinally staggered groups of hollow steel strips, that said two groups are so disposed in a mirror-inverted arrangement that a biconvex cross section is obtained, that the two strip groups are interconnected only at the base via the holder, and that the arrangement consisting of the steel strips and the holder is provided with a close-fitting, hose-like covering.

The principal advantage achieved by the invention is that the biconvex arrangement of two groups of steel strip makes the mechanical properties equal in both directions of buckling, thereby stabilizing the antenna in its mechanical behavior. By the hose-like covering, the hollow steel strips are held together. In addition, this covering insures perfect protection against contamination and corrosion, shows no bright, reflection-prone spots even if there is a certain abrasion, and simultaneously excludes the possibility of a person cutting himself.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail with reference to one embodiment thereof and in connection with the accompanying drawings, in which:

FIG. 1 is a side view of the laminated antenna in accordance with the invention;

FIG. 2 is a front view of the antenna of FIG. 1;

FIG. 3 shows the antenna of FIG. 1 in a section along line I-I and on an enlarged scale; and

FIG. 4 shows the antenna of FIG. 1 in a section along line II-II and on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 show the shape of a laminated antenna in accordance with the invention. The entire antenna lamination, which essentially consists of layers of hollow steel strips 3 (FIG. 3) of different length, is covered with a heat-shrunk hose 5. At the base, this protective covering extends beyond a holder 1 (FIG. 3) holding the steel strips together, the outlines of which are shown in FIG. 2. This holder is provided with a knurled cap nut 1b for screwing the plugged-in aerial together with the associated radio set. The free end of the antenna lamination is designed as an elastic tongue 5b. It consists of the heat-shrunk hose 5, which rises above the longest hollow steel strips by a few centimeters and, as shown in FIG. 2, is welded or glued together to form a flat tongue. This elastic extension especially prevents eye injuries.

The sectional view of FIG. 3 shows the structure of a laminated antenna in accordance with the invention. The base of the antenna is formed by the holder 1, which is provided with a brace 1a for fastening the hollow steel strips 3, divided into two groups. As can be seen in FIG. 4, the individual steel strips are slightly cambered transversely to the longitudinal direction. Each of the two groups of strips consist of a number of steel strips of different length, with the longitudinal stagger directed from the inside towards the outside and the equally arranged strip sections of the two groups staggered in the longitudinal direction, too. Only the respective outer hollow steel strips 3a are equally long. The thus staggered strip groups are disposed in a mirror-inverted arrangement as shown in FIG. 4, so that a biconvex cross section is obtained. Via the brace la, the strip groups are firmly interconnected by means of rivets 2. To achieve favorable frictional conditions, the outer, or equally long additional, hollow strips 3a may be loosely added. The free end of the laminated antenna, essentially consisting of the outer hollow steel strips 3a, is provided with a plastic or metallic protective cap 4, which holds the two strip groups together and, above all, prevents the protective covering from being pierced by the strip ends. As already mentioned, the entire arrangement described is covered with a heat-shrunk hose 5. As an essential structural element, this heat-shrunk hose holds the laminated hollow steel strips together along the entire length of the antenna, causes a mutual support of the individual strips and protects the latter against contamination, corrosion and damage. To reduce friction, the inside of the covering is provided with a lubricant such as talcum powder. As shown in FIG. 4, the hose 5 has edge reinforcements 5a in order that injuries and/or piercing of the particularly stressed longitudinal edges are/is avoided. As shown in FIG. 3, the heat-shrunk hose 5 rises a few centimeters above the free end of the hollow steel strips 3a and, as already mentioned, is welded or glued together to form an elastic tongue 5b. The hue of the heat-shrunk hose 5 is chiefly dark and the surface is dull, so that the possibility of light reflections is excluded.

What is claimed is:

1. A bendable and buckling laminated antenna of the type having a plurality of layers of hollow steel strips of different length positively interconnected at the base through a holder, comprising the antenna lamination including a pair of longitudinally staggered groups of hollow steel strips, said pair of groups being disposed in a mirror-inverted arrangement to obtain a biconvex cross section, said pair of strip groups being interconnected only at the base via the holder, the arrangement of the steel strips and the holder being provided with a close-fitting, hose-like covering.

2. The laminated antenna according to claim 1 wherein the length of the hollow steel strips increases from the inside toward the outside, and wherein all steel strips are of different length with the exception of the outer steel strips.

3. The laminated antenna according to claim 2 wherein the outer, or equally long additional, hollow steel strips are loosely added.

4. The laminated antenna according to claim 1 wherein the free end of the steel strips is provided with a protective cap.

5. The laminated antenna according to claim 1 wherein the covering is a heat-shrunk hose reinforced at the longitudinal edges and which rises above the free end of the outer steel strips, and which is fixedly joined together to form an elastic tongue.

6. The laminated antenna according to claim 5 wherein the inside of the covering is provided with a lubricant.

7. A self-erecting antenna comprising a pair of longitudinally staggered groups of hollow strips arranged to have a biconvex cross-section and means for interconnecting said strips at least at one end and enclosing said strips within a continuous sheath.

8. The antenna according to claim 7 wherein said means includes a holder interconnecting said groups at the base of the antenna only.

9. A self-erecting laminated antenna capable of being twisted or flexed in any direction from the normal comprising an antenna lamination arrangement including a pair of longitudinally staggered groups of hollow strips disposed in mirror-inverted arrangement to provide a biconvex cross-section, said pair of groups being interconnected at one end and arranged to be enclosed in a nonconductive continuous sheath. 

1. A bendable and buckling laminated antenna of the type having a plurality of layers of hollow steel strips of different length positively interconnected at the base through a holder, comprising the antenna lamination including a pair of longitudinally staggered groups of hollow steel strips, said pair of groups being disposed in a mirror-inverted arrangement to obtain a biconvex cross section, said pair of strip groups being interconnected only at the base via the holder, the arrangement of the steel strips and the holder being provided with a closefitting, hose-like covering.
 2. The laminated antenna according to claim 1 wherein the length of the hollow steel strips increases from the inside toward the outside, and wherein all steel strips are of different length with the exception of the outer steel strips.
 3. The laminated antenna according to claim 2 wherein the outer, or equally long additional, hollow steel strips are loosely added.
 4. The laminated antenna according to claim 1 wherein the free end of the steel strips is provided with a protective cap.
 5. The laminated antenna according to claim 1 wherein the covering is a heat-shrunk hose reinforced at the longitudinal edges and which rises above the free end of the outer steel strips, and which is fixedly joined together to form an elastic tongue.
 6. The laminated antenna according to claim 5 wherein the inside of the covering is provided with a lubricant.
 7. A self-erecting antenna comprising a pair of longitudinally staggered groups of hollow strips arranged to have a biconvex cross-section and means for interconnecting said strips at least at one end and enclosing said strips within a continuous sheath.
 8. The antenna according to claim 7 wherein said means includes a holder interconnecting said groups at the base of the antenna only.
 9. A self-erecting laminated antenna capable of being twisted or flexed in any direction from the normal comprising an antenna lamination arrangement including a pair of longitudinally staggered groups of hollow strips disposed in mirror-inverted arrangement to provide a biconvex cross-section, said pair of groups being interconnected at one end and arranged to be enclosed in a nonconductive continuous sheath. 